A straightforward conceptual approach for evaluating spatial conservation priorities under climate change

Despite wide evidence of a quickly changing world, systematic conservation planning analyses are usually static assuming that the biodiversity being preserved in sites do not change through time. Here we generated a comprehensive ensemble forecasting experiment for 444 amphibian species inhabiting the Atlantic Forest Biodiversity Hotspot. Models were based on four methods for modeling ecological niches, and three future climate simulations. Combinations of these models were used to estimate species occurrences. We used species occurrences to optimize the current and future representation of amphibians with different conservation targets based on their geographic range size. We compared spatial priority outcomes (variance of site selection frequency scores) under dynamic conditions, using a bi-dimensional plot in which the relative importance of each site in achieving conservation targets was assessed both for current time and to 2050. Projections for 2050 show that species richness pattern will remain approximately constant, whereas high turnover rates are forecasted. Selection frequency of several locations varied widely, with recurrent sites located at the north and southeast of the biome. As for 2050, spatial priorities concentrate in the northern part of the biome. Thirty-three sites have high priority for conservation as they play an important role now and will still stand as priority locations in 2050. We present a conceptual model for dynamic spatial conservation prioritization that helps to identify priority sites under climate change. We also call attention to sites in which risk of investment is high, and to those that may become interesting options in the future.     

From climate change predictions to actions – conserving vulnerable animal groups in hotspots at a regional scale

Current climate change is a major threat to biodiversity. Species unable to adapt or move will face local or global extinction and this is more likely to happen to species with narrow climatic and habitat requirements and limited dispersal abilities, such as amphibians and reptiles. Biodiversity losses are likely to be greatest in global biodiversity hotspots where climate change is fast, such as the Iberian Peninsula. Here we assess the impact of climate change on 37 endemic and nearly endemic herptiles of the Iberian Peninsula by predicting species distributions for three different times into the future (2020, 2050 and 2080) using an ensemble of bioclimatic models and different combinations of species dispersal ability, emission levels and global circulation models. Our results show that species with Atlantic affinities that occur mainly in the North‐western Iberian Peninsula have severely reduced future distributions. Up to 13 species may lose their entire potential distribution by 2080. Furthermore, our analysis indicates that the most critical period for the majority of these species will be the next decade. While there is considerable variability between the scenarios, we believe that our results provide a robust relative evaluation of climate change impacts among different species. Future evaluation of the vulnerability of individual species to climate change should account for their adaptive capacity to climate change, including factors such as physiological climate tolerance, geographical range size, local abundance, life cycle, behavioural and phenological adaptability, evolutionary potential and dispersal ability.     

Clade‐specific consequences of climate change to amphibians in Atlantic Forest protected areas

The rapid global decline of amphibian population is alarming because many occur for apparently unknown or enigmatic reasons, even inside protected areas (PAs). Some studies have predicted the effects of climate change on amphibians’ distribution and extinction, but the relationship and consequences of climate change to the phylogenetic structure of amphibian assemblages remain obscure. By applying robust techniques for ecological niche modeling and a cutting‐edge approach on community phylogenetics, here, we evaluate how climate change affects the geographical pattern of amphibian species richness and phylogenetic diversity in the Atlantic Forest Biodiversity Hotspot, Brazil, as well as how the phylogenetic composition of amphibian assemblages respond to climate change. We found that most species contracted their ranges and that such responses are clade specific. Basal amphibian clades (e.g. Gymnophiona and Pipidae) were positively affected by climate change, whereas late‐divergent clades (e.g. Cycloramphidae, Centrolenidae, Eleutherodactylidae, Microhylidae) were severely impacted. Identifying major changes in the phylogenetic pool represents a first step towards a better understanding of how assembly processes related to climate change will affect ecological communities. A deep analysis of the impacts of climate change not only on species, but also on the evolutionary relationships among species might foster the discussion on clade‐level conservation priorities for this imperiled fauna.     

The Reduced Effectiveness of Protected Areas under Climate Change Threatens Atlantic Forest Tiger Moths

Climate change leads to species'' range shifts, which may end up reducing the effectiveness of protected areas. These deleterious changes in biodiversity may become amplified if they include functionally important species, such as herbivores or pollinators. We evaluated how effective protected areas in the Brazilian Atlantic Forest are in maintaining the diversity of tiger moths (Arctiinae) under climate change. Specifically, we assessed whether protected areas will gain or lose species under climate change and mapped their locations in the Atlantic Forest, in order to assess potential spatial patterns of protected areas that will gain or lose species richness. Comparisons were completed using modeled species occurrence data based on the current and projected climate in 2080. We also built a null model for random allocation of protected areas to identify where reductions in species richness will be more severe than expected. We employed several modern techniques for modeling species'' distributions and summarized results using ensembles of models. Our models indicate areas of high species richness in the central and southern regions of the Atlantic Forest both for now and the future. However, we estimate that in 2080 these regions should become climatically unsuitable, decreasing the species'' distribution area. Around 4% of species were predicted to become extinct, some of them being endemic to the biome. Estimates of species turnover from current to future climate tended to be high, but these findings are dependent on modeling methods. Our most important results show that only a few protected areas in the southern region of the biome would gain species. Protected areas in semideciduous forests in the western region of the biome would lose more species than expected by the null model employed. Hence, current protected areas are worse off, than just randomly selected areas, at protecting species in the future.     

Evaluating,partitioning, and mapping the spatial autocorrelation component in ecological niche modeling: a new approach based on environmentally equidistant records

Most species data display spatial autocorrelation that can affect ecological niche models (ENMs) accuracy‐statistics, affecting its ability to infer geographic distributions. Here we evaluate whether the spatial autocorrelation underlying species data affects accuracy‐statistics and map the uncertainties due to spatial autocorrelation effects on species range predictions under past and future climate models. As an example, ENMs were fitted to Qualea grandiflora (Vochysiaceae), a widely distributed plant from Brazilian Cerrado. We corrected for spatial autocorrelation in ENMs by selecting sampling sites equidistant in geographical (GEO) and environmental (ENV) spaces. Distributions were modelled using 13 ENMs evaluated by two accuracy‐statistics (TSS and AUC), which were compared with uncorrected ENMs. Null models and the similarity statistics I were used to evaluate the effects of spatial autocorrelation. Moreover, we applied a hierarchical ANOVA to partition and map the uncertainties from the time (across last glacial maximum, pre‐insustrial, and 2080 time periods) and methodological components (ENMs and autocorrelation corrections). The GEO and ENV models had the highest accuracy‐statistics values, although only the ENV model had values higher than expected by chance alone for most of the 13 ENMs. Uncertainties from time component were higher in the core region of the Brazilian Cerrado where Q. grandiflora occurs, whereas methodological components presented higher uncertainties in the extreme northern and southern regions of South America (i.e. outside of Brazilian Cerrado). Our findings show that accounting for autocorrelation in environmental space is more efficient than doing so in geographical space. Methodological uncertainties were concentrated in outside the core region of Q. grandiflora's habitat. Conversely, uncertainty due to time component in the Brazilian Cerrado reveals that ENMs were able to capture climate change effects on Q. grandiflora distributions.     

Climate change threatens protected areas of the Atlantic Forest

Only 7 % of the Atlantic Forest Biodiversity Hotspot is currently protected, though it holds 18 % of all amphibian species in South America. How effective would the Atlantic Forest network of protected areas (PAs) be in a changing climate? Are there some intrinsic features of PAs that drive species loss or gain inside them? We addressed these questions by modeling the ecological niches of 430 amphibian species in the Atlantic Forest and projecting their distributions into three future climate change simulations. We then assessed changes in species richness inside PAs for different time frames and tested their significance via null model. The number of species should decline within Atlantic Forest network of PAs under changing climate conditions. Only altitude was a good predictor of species gains or lost inside PAs. Therefore, we suggest that new PAs established in highlands would be more effective to alleviate the effects of climate change on this imperiled fauna.     

Current and future effectiveness of protected areas for the conservation of endemic owls from the Atlantic Forest

Protected areas are essential conservation tools for mitigating the rapid decline of biodiversity. However, climate change represents one of the main challenges to their long-term effectiveness, as it induces rapid changes in the geographical distribution of many species. We used ecological niche modelling to predict the impacts of climate change on the distribution of five endemic owls in the Atlantic Forest and evaluated the effectiveness of the protected areas network for their conservation. The results indicate that the protected areas network is currently effective in terms of representativeness for most species; however, there will be a decline for all species in the coming decades because of climate change. We found that the ecoregions in the northern part of the Atlantic Forest will experience a higher loss of species, whereas those ecoregions in the southern part will be important stable climatic refuges in the future. Therefore, we emphasize the need to complement the network of protected areas to increase their representativeness in the distribution of species that will be affected by climate change, reducing species loss and increasing connectivity between suitable areas. We hope the results presented herein will serve as a basis for decision-makers to re-evaluate and improve current conservation policies and decisions in order to address the challenges posed by climate change and secure the survival of these species.     

Efficiency of protected areas in Amazon and Atlantic Forest conservation: A spatio-temporal view

The Amazon and Atlantic Forest are considered the world's most biodiverse biomes. Human and climate change impacts are the principal drivers of species loss in both biomes, more severely in the Atlantic Forest. In response to species loss, the main conservation action is the creation of protected areas (PAs). Current knowledge and research on the PA network's conservation efficiency is scarce, and existing studies have mainly considered a past temporal view. In this study, we tested the efficiency of the current PA network to maintain climatically stable areas (CSAs) across the Amazon and Atlantic Forest. To this, we used an ecological niche modeling approach to biome and paleoclimatic simulations. We propose three categories of conservation priority areas for both biomes, considering CSAs, PAs and intact forest remnants. The biomes vary in their respective PA networks' protection efficiency. Regarding protect CSAs, the Amazon PA network is four times more efficient than the Atlantic Forest PA network. New conservation efforts in these two forest biomes require different approaches. We discussed the conservation actions that should be taken in each biome to increase the efficiency of the PA network, considering both the creation and expansion of PAs as well as restoration programs.     

A macroecological approach to evolutionary rescue and adaptation to climate change

Despite the widespread use of ecological niche models (ENMs) for predicting the responses of species to climate change, these models do not explicitly incorporate any population‐level mechanism. On the other hand, mechanistic models adding population processes (e.g. biotic interactions, dispersal and adaptive potential to abiotic conditions) are much more complex and difficult to parameterize, especially if the goal is to predict range shifts for many species simultaneously. In particular, the adaptive potential (based on genetic adaptations, phenotypic plasticity and behavioral adjustments for physiological responses) of local populations has been a less studied mechanism affecting species’ responses to climatic change so far. Here, we discuss and apply an alternative macroecological framework to evaluate the potential role of evolutionary rescue under climate change based on ENMs. We begin by reviewing eco‐evolutionary models that evaluate the maximum sustainable evolutionary rate under a scenario of environmental change, showing how they can be used to understand the impact of temperature change on a Neotropical anuran species, the Schneider's toad Rhinella diptycha. Then we show how to evaluate spatial patterns of species’ geographic range shift using such models, by estimating evolutionary rates at the trailing edge of species distribution estimated by ENMs and by recalculating the relative amount of total range loss under climate change. We show how different models can reduce the expected range loss predicted for the studied species by potential ecophysiological adaptations in some regions of the trailing edge predicted by ENMs. For general applications, we believe that parameters for large numbers of species and populations can be obtained from macroecological generalizations (e.g. allometric equations and ecogeographical rules), so our framework coupling ENMs with eco‐evolutionary models can be applied to achieve a more accurate picture of potential impacts from climate change and other threats to biodiversity.     

Using niche-based modelling to assess the impact of climate change on tree functional diversity in Europe

Rapid anthropogenic climate change is already affecting species distributions and ecosystem functioning worldwide. We applied niche-based models to analyse the impact of climate change on tree species and functional diversity in Europe. Present-day climate was used to predict the distributions of 122 tree species from different functional types (FT). We then explored projections of future distributions under one climate scenario for 2080, considering two alternative dispersal assumptions: no dispersal and unlimited dispersal. The species-rich broadleaved deciduous group appeared to play a key role in the future of different European regions. Temperate areas were projected to lose both species richness and functional diversity due to the loss of broadleaved deciduous trees. These were projected to migrate to boreal forests, thereby increasing their species richness and functional diversity. Atlantic areas provided an intermediate case, with a predicted reduction in the numbers of species and occasional predicted gains in functional diversity. This resulted from a loss in species within the broadleaved deciduous FT, but overall maintenance of the group. Our results illustrate the fact that both species-specific predictions and functional patterns should be examined separately in order to assess the impacts of climate change on biodiversity and gain insights into future ecosystem functioning.     

Safeguarding Ecosystem Services: A Methodological Framework to Buffer the Joint Effect of Habitat Configuration and Climate Change

Ecosystem services provided by mobile agents are increasingly threatened by the loss and modification of natural habitats and by climate change, risking the maintenance of biodiversity, ecosystem functions, and human welfare. Research oriented towards a better understanding of the joint effects of land use and climate change over the provision of specific ecosystem services is therefore essential to safeguard such services. Here we propose a methodological framework, which integrates species distribution forecasts and graph theory to identify key conservation areas, which if protected or restored could improve habitat connectivity and safeguard ecosystem services. We applied the proposed framework to the provision of pollination services by a tropical stingless bee (Melipona quadrifasciata), a key pollinator of native flora from the Brazilian Atlantic Forest and important agricultural crops. Based on the current distribution of this bee and that of the plant species used to feed and nest, we projected the joint distribution of bees and plants in the future, considering a moderate climate change scenario (following IPPC). We then used this information, the bee’s flight range, and the current mapping of Atlantic Forest remnants to infer habitat suitability and quantify local and regional habitat connectivity for 2030, 2050 and 2080. Our results revealed north to south and coastal to inland shifts in the pollinator distribution during the next 70 years. Current and future connectivity maps unraveled the most important corridors, which if protected or restored, could facilitate the dispersal and establishment of bees during distribution shifts. Our results also suggest that coffee plantations from eastern São Paulo and southern Minas Gerais States could suffer a pollinator deficit in the future, whereas pollination services seem to be secured in southern Brazil. Landowners and governmental agencies could use this information to implement new land use schemes. Overall, our proposed methodological framework could help design novel conservational and agricultural practices that can be crucial to conserve ecosystem services by buffering the joint effect of habitat configuration and climate change.     

Climate change hastens the conservation urgency of an endangered ungulate

Global climate change appears to be one of the main threats to biodiversity in the near future and is already affecting the distribution of many species. Currently threatened species are a special concern while the extent to which they are sensitive to climate change remains uncertain. Przewalski's gazelle (Procapra przewalskii) is classified as endangered and a conservation focus on the Qinghai-Tibetan Plateau. Using measures of species range shift, we explored how the distribution of Przewalski's gazelle may be impacted by projected climate change based on a maximum entropy approach. We also evaluated the uncertainty in the projections of the risks arising from climate change. Modeling predicted the Przewalski's gazelle would be sensitive to future climate change. As the time horizon increased, the strength of effects from climate change increased. Even assuming unlimited dispersal capacity of gazelles, a moderate decrease to complete loss of range was projected by 2080 under different thresholds for transforming the probability prediction to presence/absence data. Current localities of gazelles will undergo a decrease in their occurrence probability. Projections of the impacts of climate change were significantly affected by thresholds and general circulation models. This study suggests climate change clearly poses a severe threat and increases the extinction risk to Przewalski's gazelle. Our findings 1) confirm that endangered endemic species is highly vulnerable to climate change and 2) highlight the fact that forecasting impacts of climate change needs an assessment of the uncertainty. It is extremely important that conservation strategies consider the predicted geographical shifts and be planned with full knowledge of the reliability of projected impacts of climate change.     

Geographical ecology and conservation of Eugenia L. (Myrtaceae) in the Brazilian Cerrado: Past,present and future

Human actions have caused the fragmentation of natural vegetation, habitat loss and climate change. The Cerrado, considered one of the global hotspots of diversity, has suffered great habitat loss due to these factors, which has been aggravated by the agricultural expansion that took place during the last 60 years. In this context, we chose species of the genus Eugenia L. (Myrtaceae) occurring in the Brazilian Cerrado to describe richness patterns and range loss, and determine conservation priorities for the Cerrado. Ecological niche models (ENMs) were applied to calculate the geographical range of each species in the past (Last Glacial Maximum – LGM, 21 000 years ago), present (PIP, representing current climatic conditions – 1760 years ago) and future (near future – NF, 2080–2100). These results were combined to calculate the richness of the group and also to estimate the range loss of these species in the future. Moreover, we evaluated the irreplaceability of areas for species conservation, aiming to maximize the biotic stability of Eugenia species. Our results showed that the highest species richness in the past was found in the southwestern region of the Cerrado and, currently, the richest regions are found in the central and southeastern areas. However, in the future, we predict a shift of the greatest values of richness towards the southeastern region, an area currently occupied by the Atlantic forest. Although areas with high conservation priorities were found scattered across the biome, this shift is worrisome due to the high fragmentation rate and intensive human occupation thoughout the Atlantic region. Thus, conservation efforts should focus on areas found within these limits.     

Amphibian Beta Diversity in the Brazilian Atlantic Forest: Contrasting the Roles of Historical Events and Contemporary Conditions at Different Spatial Scales

Current patterns of biodiversity distribution result from a combination of historical and contemporary processes. Here, we compiled checklists of amphibian species to assess the roles of long-term climate stability (Quaternary oscillations), contemporary environmental gradients and geographical distance as determinants of change in amphibian taxonomic and phylogenetic composition in the Brazilian Atlantic Forest. We calculated beta diversity as both variation in species composition (CBD) and phylogenetic differentiation (PBD) among the assemblages. In both cases, overall beta diversity was partitioned into two basic components: species replacement and difference in species richness. Our results suggest that the CBD and PBD of amphibians are determined by spatial turnover. Geographical distance, current environmental gradients and long-term climatic conditions were complementary predictors of the variation in CBD and PBD of amphibian species. Furthermore, the turnover components between sites from different regions and between sites within the stable region were greater than between sites within the unstable region. On the other hand, the proportion of beta-diversity due to species richness difference for both CBD and PBD was higher between sites in the unstable region than between sites in the stable region. The high turnover components from CBD and PBD between sites in unstable vs stable regions suggest that these distinct regions have different biogeographic histories. Sites in the stable region shared distinct clades that might have led to greater diversity, whereas sites in the unstable region shared close relatives. Taken together, these results indicate that speciation, environmental filtering and limited dispersal are complementary drivers of beta-diversity of amphibian assemblages in the Brazilian Atlantic Forest.     

The conservation physiology of seed dispersal

At a time when plant species are experiencing increasing challenges from climate change, land-use change, harvesting and invasive species, dispersal has become a very important aspect of plant conservation. Seed dispersal by animals is particularly important because some animals disperse seeds to suitable sites in a directed fashion. Our review has two aims: (i) to highlight the various ways plant dispersal by animals can be affected by current anthropogenic change and (ii) to show the important role of plant and (particularly) animal physiology in shaping seed-dispersal interactions. We argue that large-bodied seed dispersers may be particularly important for plant conservation because seed dispersal of large-seeded plants is often more specialized and because large-bodied animals are targeted by human exploitation and have smaller population sizes. We further argue that more specialized seed-dispersal systems on island ecosystems might be particularly at risk from climate change both owing to small population sizes involved but also owing to the likely thermal specialization, particularly on tropical islands. More generally, the inherent vulnerability of seed-dispersal mutualisms to disruption driven by environmental change (as well as their ubiquity) demands that we continue to improve our understanding of their conservation physiology.     

Forecasting cloud forest in eastern and southern Mexico: conservation insights under future climate change scenarios

Assuming that co-distributed species are exposed to similar environmental conditions, ecological niche models (ENMs) of cloud forest species were developed to study how climate change could affect the distribution of cloud forest in eastern and southern Mexico for the year 2050. Using ENM-based predictions and climatic data for IPCC climate change A2 and B2 scenarios, we observed 54–76% reduction of the cloud forest, mainly in the northern region of its current range (Sierra Madre Oriental) and the Pacific slope of Chiapas. With predicted 2050 climate change, cloud forest in the Los Tuxtlas region and El Cielo Biosphere Reserve may face a serious threat of extinction due to the observed upward migration to higher elevations. Our results add to recent studies detecting negative impacts of climate change in montane forests, but the negative impacts of climate change might be exacerbated by current environmental changes in the region. The integration of ecological-niche characteristics of cloud forest in conjunction with projections of extreme climate scenarios constitute a suitable tool to define appropriate areas in which proactive conservation and management strategies should be focused.     

Tools for integrating range change,extinction risk and climate change information into conservation management

Ecological niche models (ENMs) are the primary tool used to describe and forecast the potential influence of climate change on biodiversity. However, ENMs do not directly account for important biological and landscape processes likely to affect range dynamics at a variety of spatial scales. Recent advances to link ENMs with population models have focused on the fundamental step of integrating dispersal and metapopulation dynamics into forecasts of species geographic ranges. Here we use a combination of novel analyses and a synthesis of findings from published plant and animal case studies to highlight three seldom recognised, yet important, advantages of linking ENMs with demographic modelling approaches: 1) they provide direct measures of extinction risk in addition to measures of vulnerability based on change in the potential range area or total habitat suitability. 2) They capture life‐history traits that permit population density to vary in different ways in response to key spatial drivers, conditioned by the processes of global change. 3) They can be used to explore and rank the cost effectiveness of regional conservation alternatives and demographically oriented management interventions. Given these advantages, we argue that coupled methods should be used preferentially where data permits and when conservation management decisions require intervention, prioritization, or direct estimates of extinction risk.     

Climate warming and the decline of amphibians and reptiles in Europe

Aim We explore the relationship between current European distributions of amphibian and reptile species and observed climate, and project species potential distributions into the future. Potential impacts of climate warming are assessed by quantifying the magnitude and direction of modelled distributional shifts for every species. In particular we ask, first, what proportion of amphibian and reptile species are projected to lose and gain suitable climate space in the future? Secondly, do species projections vary according to taxonomic, spatial or environmental properties? And thirdly, what climate factors might be driving projections of loss or gain in suitable environments for species? Location Europe. Methods Distributions of species are modelled with four species–climate envelope techniques (artificial neural networks, generalized linear models, generalized additive models, and classification tree analyses) and distributions are projected into the future using five climate‐change scenarios for 2050. Future projections are made considering two extreme assumptions: species have unlimited dispersal ability and species have no dispersal ability. A novel hybrid approach for combining ensembles of forecasts is then used to group linearly covarying projections into clusters with reduced inter‐model variability. Results We show that a great proportion of amphibian and reptile species are projected to expand distributions if dispersal is unlimited. This is because warming in the cooler northern ranges of species creates new opportunities for colonization. If species are unable to disperse, then most species are projected to lose range. Loss of suitable climate space for species is projected to occur mainly in the south‐west of Europe, including the Iberian Peninsula, whilst species in the south‐east are projected to gain suitable climate. This is because dry conditions in the south‐west are projected to increase, approaching the levels found in North Africa, where few amphibian species are able to persist. Main conclusions The impact of increasing temperatures on amphibian and reptile species may be less deleterious than previously postulated; indeed, climate cooling would be more deleterious for the persistence of amphibian and reptile species than warming. The ability of species to cope with climate warming may, however, be offset by projected decreases in the availability of water. This should be particularly true for amphibians. Limited dispersal ability may further increase the vulnerability of amphibians and reptiles to changes in climate.     

Climate Change and American Bullfrog Invasion: What Could We Expect in South America?

Background

Biological invasion and climate change pose challenges to biodiversity conservation in the 21^st century. Invasive species modify ecosystem structure and functioning and climatic changes are likely to produce invasive species'' range shifts pushing some populations into protected areas. The American Bullfrog (Lithobates catesbeianus) is one of the hundred worst invasive species in the world. Native from the southeast of USA, it has colonized more than 75% of South America where it has been reported as a highly effective predator, competitor and vector of amphibian diseases.

Methodology/Principal Findings

We modeled the potential distribution of the bullfrog in its native range based on different climate models and green-house gases emission scenarios, and projected the results onto South America for the years of 2050 and 2080. We also overlaid projected models onto the South American network of protected areas. Our results indicate a slight decrease in potential suitable area for bullfrog invasion, although protected areas will become more climatically suitable. Therefore, invasion of these sites is forecasted.

Conclusion/Significance

We provide new evidence supporting the vulnerability of the Atlantic Forest Biodiversity Hotspot to bullfrog invasion and call attention to optimal future climatic conditions of the Andean-Patagonian forest, eastern Paraguay, and northwestern Bolivia, where invasive populations have not been found yet. We recommend several management and policy strategies to control bullfrog invasion and argue that these would be possible if based on appropriate articulation among government agencies, NGOs, research institutions and civil society.     

Projected changes in distributions of Australian tropical savanna birds under climate change using three dispersal scenarios

Identifying the species most vulnerable to extinction as a result of climate change is a necessary first step in mitigating biodiversity decline. Species distribution modeling (SDM) is a commonly used tool to assess potential climate change impacts on distributions of species. We use SDMs to predict geographic ranges for 243 birds of Australian tropical savannas, and to project changes in species richness and ranges under a future climate scenario between 1990 and 2080. Realistic predictions require recognition of the variability in species capacity to track climatically suitable environments. Here we assess the effect of dispersal on model results by using three approaches: full dispersal, no dispersal and a partial-dispersal scenario permitting species to track climate change at a rate of 30 km per decade. As expected, the projected distributions and richness patterns are highly sensitive to the dispersal scenario. Projected future range sizes decreased for 66% of species if full dispersal was assumed, but for 89% of species when no dispersal was assumed. However, realistic future predictions should not assume a single dispersal scenario for all species and as such, we assigned each species to the most appropriate dispersal category based on individual mobility and habitat specificity; this permitted the best estimates of where species will be in the future. Under this "realistic" dispersal scenario, projected ranges sizes decreased for 67% of species but showed that migratory and tropical-endemic birds are predicted to benefit from climate change with increasing distributional area. Richness hotspots of tropical savanna birds are expected to move, increasing in southern savannas and southward along the east coast of Australia, but decreasing in the arid zone. Understanding the complexity of effects of climate change on species' range sizes by incorporating dispersal capacities is a crucial step toward developing adaptation policies for the conservation of vulnerable species.